Demand for high data rates has been driving development and standardization efforts for next generation wireless systems, such as evolved universal terrestrial radio access (E-UTRA) and IEEE 802.11n. To achieve high data rates, high-rate channel coding and higher order modulation are needed, which often causes less reliable transmission. One remedy for this is using transmit diversity, such as space-time block code (STBC).
FIG. 1 is a block diagram of a conventional transmitter 100 employing STBC. Incoming bits 105 are coded by a channel encoder 110. The output 115 of the channel encoder 110, (i.e., coded bits), are passed to a puncturer 120, where some bits are deleted, (i.e., punctured), according to a predetermined puncturing pattern. The deleted bits are often referred to as “stolen” bits 125 and are not transmitted to a receiver in any form. The stolen bits are placed in a data sink 130, (which is merely a conceptual component), for disposal. The surviving bits 135 are interleaved by an interleaver 140, to avoid burst errors. The interleaved surviving bits 145 are then mapped to channel symbols 155 by a mapper 150, such as quadrature phase shift keying (QPSK), or 16 quadrature amplitude modulation (16 QAM), or the like. The channel symbols 155 are finally coded by an STBC encoder 160 and transmitted over the air via antennas 165. STBC provides full diversity at the symbol level, but it does not provide additional coding gain.